# Shock --- **Shock** is a critical condition brought on by the sudden drop of blood flow or [[tissue perfusion]] in the body. Shock it may develop slowly over time or quite rapidly. It can be quite dangerous, and lead to [[multiple organ dysfunction syndrome]], or **MODS**, where there is an alteration of function of two or more organs in an acutely ill person, cush that interventions are necessary to support continued organ function. It has a 75% mortality rate, so preventing shock from progressing that far is a high priority. MODS contributes to about 50% of ICU deaths. There are lots of ways this can be brought about, but common physiologic responses to shock are: - hypoperfusion of tissues - hypermetabolism - meaning fat metabolism (i.e. [[cellular respiration|anaerobic respiration]]) - [[lactate]] goes up - activation of the [[inflammation]] response >[!health] It can happen to anyone >Any patient with any disease state may be at risk for developing shock. Even [[pressure injury|pressure injuries]] can cause shock—all the more reason to prevent them! ## Stages of Shock The body goes though three stages of shock: **compensatory**, **progressive stage** and **irreversible**. ### The Compensatory Stage In the **compensatory stage** of shock the body starts to have a shock reaction but is essentially trying to course correct. There are symptoms, but for the most part they appear fine. For one they may appear confused. The body is shunting blood from less important places, like the skin, kidneys, GI tract, so we see they might be cool and clammy with hypoactive [[abdominal assessment|bowel sounds]]. There is also vasoconstriction, which increases the heart rate and heart contractility in order to maintain [[cardiac output]]/[[blood pressure]]. Cells in the body aren't getting blood, so those that can switch to [[cellular respiration|anaerobic respiration]], which can lead to [[acid-base balance|acidosis]]. As a result the respiration rate may increase to compensate. There is sometimes a "feeling of impending doom". The patient will express that "something just doesn't feel right" ### The Progressive Stage In the **progressive stage**, (also sometimes called the **decompensated stage**) the body is no longer able to compensate for the loss of perfusion, and we start to see some real hard symptoms. During this stage there is a [[homeostasis|positive feedback]] where the symptoms of shock cause more shock. The organs suffer from hypoperfusion and start to fail. The heart starts to show [[arrhythmia]], there is ischemia of the heart tissue. The lungs have decreased pulmonary blood flow so they become further hypoxic and CO2 levels increase. Alveoli collapse and palmary edema occurs. Kidneys ([[acute kidney injury]]), liver and GI are damaged. Mechanisms that regulate the [[blood pressure]] are no longer sufficient. BP and MAP tank, which drops the GFR entirely. We may also see [[disseminated intravascular coagulation]] as a complication of shock. It happens because the body just starts clotting up everywhere due to the overwhelming inflammation response, which uses up all the clotting factors in the body. With all the clotting factors gone the blood just starts coming out anywhere it can. ### The Irreversible Stage The **irreversible stage** is when the body has depleted the necessary resources and the patient cannot recover. The patient is usually unconscious and does not respond to treatment. Blood pressure remains very low. Multiple organ damage progresses to complete organ failure, and acidosis from anaerobic metabolism worsens. Treatment for shock does not stop when the patient progresses into the irreversible stage, and it is only every judged as such in retrospect. ## Treating Shock Treating shock emphasizes recognizing the symptoms and preventing the progression of shock, as well as identifying and treating the underlying cause of the shock. Though the specific interventions will vary depending on they type of shock the patient is in, there are some things we do in all cases: - Replace the fluids in order to restore the volume of blood in the blood vessels. - Give vasoactive medications to restore [[autonomic nervous system|vasomotor tone]] and improve cardiac function. - Provide nutritional support to address metabolic requirements. ### Shock Workup A **shock workup** or a **sepsis workup** is a set of labs drawn when a patient is showing symptoms of shock. One common one is to detect the levels of **lactate** in the blood. High levels of lactate in the blood can indicate hypoxia or other conditions leading excess production or insufficient clearing of lactate from the blood. ## Types of Shock There are many different causes and types of shock. Broadly speaking there are four types of shock: hypovolemic, distributive, cardiogenic, and obstructive shock. ### Hypovolemic Shock **Hypovolemic shock** sometimes called **hemorrhagic shock** is shock due to a loss of [[body fluids]]—i.e. bleeding to death. This can be due to external or internal bleeding, and the first thing to do with a patient undergoing hypovolemic shock is to stop the bleeding and replace the fluids if possible. It is not necessarily due to hemorrhaging either, but can also be caused by excessive GI losses (vomiting, diarrhea), urination, losses through the skin (i.e. via [[burns]]) and "third space loss" such as fluid building up in an organ. ### Distributive Shock **Distributive shock** is a state of *relative* hypovolemia resulting from a systemic peripheral vasodilation. Normally [[blood vessels|vasodilation]] happens only in one place, and the body can easily compensate that loss of fluid. However, when all the blood vessels dilate, there is not enough fluid to go around. Distributive shock is generally treated with vasoconstrictors and fluid replacement. - **Septic shock** is a late and deadly complication of [[sepsis]] occurs when there is a [[toxin]] or infection in the body or bloodstream or something like that. - **Toxic shock syndrome** (TSS) is a specific form of septic shock caused by the "[[toxin#Characterized by Structure|superantigen]]" toxins of the Staphylococcus and Streptococcus bacteria. TSS can occur from tampon use, especially "super-absorbent" ones that people tend to keep in for extended periods of time. - **Anaphylactic shock** occurs during a severe [[Type I hypersensitivity]] event. - [[spinal cord injury#Complications|neurogenic shock]] can happen in response to an injury to the central nervous system. ### Cardiogenic Shock **Cardiogenic shock** arises from a problem with the pump, i.e. the [[heart]]. Essentially there is a decrease of [[cardiac output]] and this causes systemic hypoprofusion. Problems with the heart can be: - Cardiomyopathies such as [[myocardial infarction|MI]], [[coronary circulation|coronary heart disease]], cardiac arrest and myocarditis - [[arrhythmia|Arrhythmias]] which can be brady or tachy. - Mechanical problems such as a rupture of the papillary muscles or the [[heart|chordae tendineae]]. ### Obstructive Shock **Obstructive shock** arises from a blockage of the circulation, typically from mechanical problems such as the heart being unable to expand due to [[pneumothorax]] or other things along those lines. ___